Method of and apparatus for impact molding galvanic cell cathodes



Aug. 3, 1965 H. K. AMTHOR ETAL 3,198,862

METHOD OF AND APPARATUS FOR IMPACT MOLDING GALVANIC CELL CATHODES 2 Sheets-Sheet 1 Filed June 15, 1962 INVENTORS HELMUT K. AMTHOR PHILLIP B. DOLL aydj ATTORNE 1965 H. K. AMTHOR ETAL 3,198,362

METHOD OF AND APPARATUS FOR IMPACT MOLDING GALVANIC CELL CATHODES Filed June 15, 1962 2 Sheets-Sheet. 2

\\\\ I I I /56 i 22 I :1 li g I I I f0 nvvrzzwom- HELMUT K. AMTHOR PHILLIP B. DOLL By m Q ATTOR/VE United States Patent 3,198,362 METHOD OF AND APPARATUS FUR IMPACT MOLDING GALVANEC CELL CATHODE Helmut K. Arnthor, Rocky River, and Phillip B. Doll,

Lakewood, ()hio, assignors to Union Carbide Corporation, a corporation. of New York Filed June 15, 1962, Ser. No. 202,793 1% Claims. ((31. 264-161) This invention relates to the impact molding of various shaped cathodes for use in galvanic cells, and more particularly to an improved method and apparatus for manu facturing the same.

An excellent process for molding hollow cathodes is disclosed in copending United States application Serial No. 145,325, filed October 16, 1961, and now Patent No. 3,156,749, the assignee of the subject invention being also the assignee of the above-referred to application. The process disclosed in the copending application comprises driving a ram having a smaller diameter than a cylindrical galvanic cell container into the container, the bottom of which contains more cathodic mix than is required to form the cathode of the particular cell. The impact of the ram forces the cathodic mix into the space between the ram and the container wall thereby forming a hollow cylindrical cathode, and the excess cathodic mix is forced out of the cell container via a plurality of flutes on the side of the ram which extend above the cell container when the ram is at its lowermost position.

After the expulsion of the excess cathodic mix and prior to the withdrawal of the ram, the ram is rotated slightly to break the adhesion between the formed cathode and the ram. This rotation also serves to smooth over the inner surface of the molded cathode.

This disclosed method is, however, suitable only for making hollow cylindrical cathodes. For example, it could not be used for making cathodes for flat-type alkaline round cells. In order to make flat disc cathodes a ram having substantially the same diameter as the inside diameter of the cell container must be used. The

ram must also have means by which the excess cathodic mix can escape from beneath the bottom face of the ram. Using a ram having no escape means provided in its bottom face and an excess of cathodic mix which is somewhat incompressible to make flat disc cathodes could result in premature failure of the ram, press or other member of the apparatus since the stresses and deflections resulting therefrom would be exceedingly high.

The principal object of the invention is to provide an improved impact molding process suitable for forming cathodes of various shapes and sizes including those of the flat disc-like shape.

The above and other objects of the invention are achieved by the impact molding of dry or moisturized powder-like cathodic mixes in place within a cell container with a molding ram having means by which excess cathodic mix can escape from beneath the face of the ram, and in addition along the side of the ram, if desired.

The invention will be more readily understood by reference to the accompanying drawing, wherein:

FIGURE 1 is a front elevational view partially in section of a press suitable for carrying out the process of the invention;

FIGURE 2 is an enlarged vertical partially sectioned view of the ram in FIGURE 1;

FIGURE 2a is an end view of the ram shown in FIG- URE 2;

FIGURE 3 is a vertical partially sectioned view of a modified ram suitable for use in the press of FIGURE 1;

and shape, etc.

3,198,862 Patented Aug. 3, 1965 ice FIGURE 4 is an end view of the ram shown in FIG- URE 3;

FIGURE 5 is a partially sectioned elevational view of another modified ram; and

FIGURE 6 is a partially sectioned elevational view of yet another modified ram.

Refering now to the drawing and particularly to FIG- URE 1, a cell container 10 is shown in position in a cavity 12 of a die bushing 14. The die bushing 14 is situated within a die housing 16 of a punch press 18. The cell container 10 is positioned directly over an ejector pad 20. An ejector pin 21, situated directly beneath the ejector pad 20, is used to remove the cell container 10 from the cavity 12. A ram 22 is provided within the upper portion 24 of the press 18 and is moveable with respect thereto.

A stripper ring 26 is held down against the die housing 16 by a stripper bridge 28. The function of the stripper ring 26 is to retain the cell container 10 in place when the ram 22 is withdrawn during the upstroke cycle of the press 18. In the apparatus of FIGURE 1, a ram rotating cam 30 is secured and phase synchronized with the ram 22 and a ram holder 32 by means of a machine screw 34 and ram flange 36. I

Fabricating hollow cylindrical cathodes by means of a fluted ram frequently requires a slight rotation prior to withdrawal of the ram from the container. In the press of FIGURE 1 rotation of the ram 22 is accomplished upon the axial movement of the upper portion 24 of the press 18 on its upstroke cycle, and upon the action of an actuating element or cam pin 38 which rides in an oblique slot 40 provided on the cam 30, thus causing the ram 22 to rotate a small angle. During a dwell and small period of the upstroke cycle of the press 18 a ram holddown spring 42 maintains the ram 22 within the cell container 10 until the rotation is complete.

In the process of the instant invention the ram 22 is driven into a partially precompressed cathodic mix or into a plurality of pellets made from'a cathodic mix. By this impact action, a cathode 44 is formed into the desired shape outlined by the space between the ram 22 and the inner walls of the cell container 10.

As will be seen in FIGURES 2 and 2a, the excess cathodic mix will escaperapidly from beneath the bottom face 46 of the ram 22 by means of a plurality of obliquely extending internal passageways 48 which communicate with a plurality of flutes 50 provided in theside of the ram 22, and thus it is ejected from the cell container 10.

These internal passageways 48 extend from openings 52 at the bottom face 46 of the ram 22 to the flutes 50. The number, size, shape and angularity of the passageways is a function of the mix consistency, cathode size The number of flutes need not be the same as the number of passageways. If desired, additional blind flutes 54 may suitably be used to aid in providing further expulsion outlets for the overflow or excess mix from the cell container.

The flutes 50 extend above the cell container 10 when the ram 22 is in its lowermost position. Upon the upstroke cycle of the press 18, the ram 22 is withdrawn from the cell container 10. and the formed cathode 44. Subsequently, the ejector pin 21 forces the ejector pad 20 to remove the cell container from the cavity 12. It will be noted that a slight rotation is preferable when using this type of ram to make hollow cylindrical cathodes.

In FIGURES 3 and 4 a modified ram '56 for use in the apparatus of FIGURE 1 is shown. The ram 56 is provided with a plurality of channels 57 at its bottom face 58. These channels communicate with a plurality of flutes59 provided in the side of the ram 56 by way of a plurality of narrow slots 69 located at the lower end of the ram 56.

When making fiat solid cathodes of any shape in the apparatus of FIGURE 1, the ram 22 illustrated by FIG- URES 2 and 2a is preferred over the modified ram shown in FIGURES 3 and 4. However, it will be appreciated that in the fabrication of flat solid cathodes a suitable ram having substantially the same diameter as the inside diameter of the cell container is required. The ram must also be provided with rapid escape means for any excess mix from beneath the bottom face of the ram. As shown in FIGURES 2 and 2a the ram 22 is preferable for making fiat solid cathodes because the internal passageways 48 are instrumental in guiding and dispersing the excess cathodic mix quickly to flutes 50 and out of the cell container and in providing a smooth cathode surface finish.

The ram 56 shown in FIGURES 3 and 4 is also suitable for making fiat cathodes if it is of substantially the same diameter as the inside diameter of the cell container. However, the ram 56 preferably requires a small rotation, whereas the ram 22 does not require rotation prior to withdrawal of the ram from the cell container. Neverthe less, if ram 22 is used to fabricate hollow cylindrical cathodes it is also preferable to rotate the ram a small amount prior to withdrawal.

In FIGURE another modified ram 62 is shown. The ram 62 contains a central manifold or axial passageway 64 which communicates with at least one, preferably three, oblique passageways 65 having openings at the bottom face 66 of the ram 62. More than one axial passageway can be used depending upon the size of the cathode to be made and the consistency of the mix. A plurality of lower intersecting passageways 68 connect the axial passageway 64 with the lower side of the ram 62. A plurality of upper intersecting passageways 70 connect the axial passageway 64 with the upper side of the ram 62. These upper intersecting passageways 70 have openings at the side of the ram 62 above the container when the ram is in its lowermost position.

The axial passageway 64 is preferably tapered or graduated in diameter (not shown) and is smallest in diameter at the lowermost end of the ram 62. The upper and lower intersecting passageways 68 and 70 can suitably be replaced by a plurality of elongated slots (not shown) milled completely through the ram 62. They may be dis posed perpendicular to the ram and suitably 90 degrees apart from each other.

Using ram 62 in the apparatus of FIGURE 1 provides the apparatus with an adaptation for making non-circular hollow cathodes of any shape such as square or rectangular. Of course, the conventional cylindrically shaped cathodes can also be made with this type of ram. Since the side of the ram 62 has no flutes or other grooves except the small openings, no rotation of the ram on withdrawal is necessary. The small openings of the lower passageways on the side of the ram and the bottom face openings are sheared off cleanly. In addition, the ram smooths over the side sheared olf areas while it is being withdrawn from the formed cathode and container.

In FIGURE 6 another modified ram 72 is illustrated. A plurality of oblique passageways 74 connect the bottom face 76 of the ram 72 to a plurality of internal passageways 78. The internal passageways 78 communicate with a plurality of upper intersecting passageways 86 which are located in an area where the mix can be ejected when the ram 72 is at its lowest position in a particular cell container.

This type of ram is also suitable for making flat cathodes since all of the excess cathodic mix is expelled through internal passageways. The peripheral portion of the ram is smooth and free from flutes or other openings thereby providing a surface which can be made to have a free. sliding fit with the inside diameter of the cell container. There is no need to rotate this ram when making flat cathodes. Thus, this ram can be used with the apparatus of FIGURE 1 to make fiat cathodes of any shape.

In all the modifications shown the ram bottom face can be anywhere from convex to concave in shape, which- 4 ever is preferable and advantageous for each particular cell design. Of course, the rams may be provided with any desirable radius at their bottom edges and they can be slightly tapered to facilitate alignment.

It will be appreciated that many combinations of the escape means described in the modified rams disclosed herein are possible and will be apparent to those skilled in the art. For example, the ram can be suitably designed for molding tubular shaped cathodes having both ends open. it will also be appreciated by those skilled in the art that other machines such as a rotary compacting machine or a slow speed hydraulic press would alsobe suitable for the practice of the invention.

What is claimed is:

1. A process for impact molding a cathode in place in a cell container comprising the steps of dispensing an excess of cathodic mix into said cell container, driving a ram provided with internal passage means for expelling said excess of said cathodic mix from beneath the bottom face of said ram into said cathodic mix, removing said excess of said cathodic mix through said passage means while the remainder of said cathodic mix is molded into a cathode between said ram and said cell container, ro tating said ram a slight amount prior to withdrawal from said container whereby said excess of said cathodic mix in said passage means is sheared and severed off from said formed cathode and then removing said ram from said container thus forming a finished cathode-container structure.

2. A process for impact molding a flat cathode in place in a cell container comprising the steps of dispensing an excess of cathodic mix into said cell container, driving a ram of substantially the same diameter as the inside diameter of said container and provided with internal passage means for expelling said excess of said cathodic mix from beneath the bottom face of said ram and from said container into said cathodic mix, removing said excess of said cathodic mix through said passage means while the remainder of said cathodic mix is molded into a flat cathode between said cell container and said bottorn face of said ram rotating said ram a slight amount prior to withdrawal from said container whereby said excess of said cathodic mix in said passage means is sheared and severed off from said formed cathode, and then removing said ram from said container thus forming a finished cathode-container structure.

3. The process of claim 2 for impact molding fiat cathodes wherein said passage means in said ram comprises at least one internal passageway having at least one lower opening at the bottom face of said ram and at least one upper opening located in the side of said ram, said internal passageway and said openings providing an escape route for said excess mix when said ram is in said container, said excess of said cathodic mix being expelled from beneath the bottom face of said ram and from said container via said passageway and said openings.

4. A process for impact molding cylindrical cathodes comprising the steps of dispensing an excess of cathodic mix into a cylindrical galvanic cell container, driving a ram into said cathodic mix, the diameter of said ram being less than the inside diameter of said cell container, said ram being provided with a plurality of oblique internal passageways extending from Openings at the bottom face of said ram to a plurality of flutes located in the side of said ram, said flutes extending above said container when said ram is in said container, said excess of said cathodic mix being expelled from beneath the bottom face of said ram and from said container through said internal passageways and said flutes, the remainder of said cathodic mix being molded into a cylindrical cathode between said ram and the inner wall of said cell container, and rotating said ram a slight amount prior to withdrawal from said container whereby said excess of said cathodic mix is sheared and severed off from said formed cathode thus forming finished cathode-container structure.

5. The process of claim 4 wherein said ram is held in the down position by a spring until said rotation is completed.

6. A process for impact molding cylindrical cathodes comprising the steps of dispensing an excess of cathodic mix into a cylindrical galvanic cell container, driving a ram into said cathodic mix, the diameter of said ram being less than the inside diameter of said cell container, said ram being provided with at least one axial passageway having at least one Opening in the bottom face of said ram, the lower portion of said axial passageway communicating with a plurality of lower intersecting passageways having openings at the lower side of said ram, the upper portion of said axial passageway communicating with a plurality of upper intersecting passageways having openings in the upper side of said ram, said openings in the upper side of said ram lying above said container when said ram is in said container, said excess of said cathodic mix being expelled from beneath the bottom face of said ram and from said container via said lower intersecting passageways, said axial passageway, said upper intersecting passageways and said openings, the remainder of said cathodic mix being molded into a cylindrical cathode between said ram and the inner wall of said cell container, and rotating said ram a slight amount prior to withdrawal from said container whereby said excess of said cathdoic mix is sheared and severed oil from said formed cathode thus forming a finished cathode-container structure.

7. An apparatus suitable for impact molding a cathode in place in a cylindrical container containing an excess of cathodic mix therein, which comprises, a press, said press comprising a movable upper portion having a cylindrical ram provided with internal passage means for expelling said excess of said cathodic mix from said cylindrical container, a stationary lower portion provided with a cavity for receiving said cylindrical container containing said excess of cathodic mix which is in line with said ram, a cam having an oblique slot for controlling the rotation of said ram, resilient means urging said ram downwardly, means for moving said ram in and out of said cavity, at least a portion of said passage means extending above said cavity when said ram is within said cavity and a cam pin rigidly attached to said movable upper portion of said press which rides in said oblique slot of said cam, whereby said ram rotates from about 5 to about 30 prior to the initial withdrawal of said ram from said cavity and whereby said excess of said cathodic mix in said passage means is sheared and severed ofi from said formed cathode-container structure.

8. An apparatus suitable for impact molding a cathode in place in a cupped-shaped container containing an excess of cathodic mix therein, which comprises, a press, said press comprising a movable upper portion having a ram of a compatible shape with said container, said ram being provided with at least one main internal passageway and a plurality of smaller internal passageways intersecting said main passageway and the exterior surface of said ram for expelling said excess of said cathodic mix from said container, a stationary lower portion provided with a cavity for receiving said container containing said excess of said cathodic mix which is in line with said ram, a cam havng an oblique slot for controlling the rotation of said ram, resilient means urging said ram downwardly, means for moving said rarn in and out of said cavity, said main passageway extending above said cavity when said ram is within said cavity, and a cam pin rigidly attached to said movable upper portion of said press which rides in said oblique slot of said cam, whereby said ram rotates from about 5 to about 30 prior to the initial withdrawal of said ram from said cavity and whereby said excess of said cathodic mix in said smaller passageways is sheared and severed off from said formed cathode-container structure.

9. An apparatus suitable for impact molding a cathode in place in a cylindrical container containing an excess of cathodic mix therein, which comprises, a press, said press comprising a movable upper, portion having a ram of a diameter less than the diameter of said cylindrical container, said ram being provided with at least one main internal passageway and a plurality of internal passageways intersecting said main passageway and the bottom wall and side walls of said ram for expelling said excess of said cathodic mix from beneath the bottom face of said ram and from said container, a stationary lower portion provided with a cavity for receiving said container containing said excess of said cathodic mix which is in line with said ram, a cam having an oblique slot for controlling the rotation of said ram, resilient means urging said ram downwardly, means for moving said ram in and out of said cavity, said main passageway extending above said cavity When said ram is within said cavity, and a Cam pin rigidly attached to said movable upper portion of said press which rides in said oblique slot of said cam, whereby said ram rotates from about 5 to about 30 prior to the initial withdrawal of said ram from said cavity and whereby said excess of said cathodic mix in said intersecting passageways is sheared and severed ofi from said formed cathode-container structure.

it). An apparatus suitable for impact molding a cathode in place in a container containing an excess of cathodic mix therein, which comprises, a press, said press comprising a movable upper portion having a cylindrical rarn provided with internal passageways extending from openings at the bottom face of said ram to a plurality of flutes located in the side of said ram for expelling said excess of said cathodic mix from said container, said flutes extending above said container when said ram is in said container, a stationary lower portion provided with a cavity for receiving said container containing said excess of said cathodic m x which is in line with said ram, a cam having an oblique slot for controlling the rotation of said ram, resilient means urging said ram downwardly, means for moving said ram in and out of said cavity, and a cam pin rigidly attached to said movable upper portion of said press which rides in said oblique slot of said cam, whereby said ram rotates from about 5 to about 30 prior to the initial withdrawal of said ram from said cavity and whereby said excess of said cathodic mix in said passageways and flutes is sheared and severed off from said formed cathode-container structure.

References Cited by the Examiner UNITED STATES PATnNTS 1,195,118 8/16 Weida.

2,040,674 5/36 Severance et al.

2,359,674 10/40 Pollock 18--16.5 X 2,659,132 11/53 Leontis et al.

3,053,713 9/62 Juras l8-59 X FOREIGN PATENTS 505,815 12/54 Italy.

ROBERT F. WHITE, Primary Examiner.

MORRIS LIEBMAN, Examiner. 

1. A PROCESS FOR IMPACT MOLDING A CATHODE IN PLACE IN A CELL CONTAINER COMPRISING THE STEPS OF DISPENSING AN EXCESS OF CATHODIC MIX INTO SAID CELL CONTAINER, DRIVING A RAM PROVIDED WITH INTERNAL PASSAGE MEANS FOR EXPELLING SAID EXCESS OF SAID CATHODIC MIX FROM BENEATH THE BOTTOM FACE OF SAID RAM INTO SAID CATHODIC MIX, REMOVING SAID EXCESS OF SAID CATHODIC MIX THROUGH SAID PASSAGE MEANS WHILE THE REMAINDER OF SAID CATHODIC MIX IS MOLDED INTO A CATHODE BETWEEN SAID RAM AND SAID CELL CONTAINER, ROTATING SAID RAM A SLIGHT AMOUNT PRIOR TO WITHDRAWAL FROM SAID CONTAINER WHEREBY SAID EXCES OF SAID CATHODIC MIX IN SAID PASSAGE MEANS IS SHEARED AND SEVERED OFF FROM SAID FORMED CATHODE AND THEN REMOVING SAID RAM FROM SAID CONTAINER THUS FORMING A FINISHED CATHODE-CONTAINER STRUCTURE. 